My "male" Swordtail

[fishy_wishy]

Wow I really thought it was a female when I first looked! but I also see the gonopodium so looks like a male, I wonder what the 'gravid spot' is?

 

[fluttermoth]

The so-called 'gravid spot' is part of the fish's gut.
 
The reason it's often thought to denote females is because it can, in the eyes of an experienced livebearer keeper, be used to determine the stage of pregnancy, as the 'womb' of the fish is right next to it and the developing fry push on that part of the gut. moving it and making it more visible; .
 
I read some research, fairly recently (although I can't find it now

), that confirmed that livebearers cannot change sex. They certainly can appear to, in that some are late developing males and others old females that are producing less female sex hormones and so take on male characteristics, as TLM rightly pointed out, but they are not fully functioning.

 

[fishy_wishy]

Interesting , can all male livebearers appear have this?

 

[fluttermoth]

The 'gravid spot'? Yes, they can.

 

[RockabillyGuy]

Hi all, and Happy new year!
 
 Hi andriab! how is your fish? Is she(he) healthy?
 How this fish looks like now?